Water Pump Pulley and Clutch Fan

[EMCD]

That's what I was thinking of. I probably got to yank out the rad to make it fit just right. While I'm at it, I'll put in a wire coil in the lower house. I hear people use coat hangers. Is that a good idea? How long of a coil do I need?

[CUDA JAS]

"the alum pulley might be 3/16 thicker , I would want 1" minimum between the fan & rad"

I agree.  You want 1" between the clutch face and the rad though...not the fan blades.  If you would be using a fixed fan, then 1" from the blades.  There will be some fore/aft movement of the water pump bearing as well as some engine mount movement.  1" should be a safe distance.  I've seen some pictures where there was 1/2" clearance and the clutch kissed the rad.  It didn't cause a leak but the fins were damaged.

So what is more important...the distance between the rad and the fan or the position of the rad in the shroud.

We were talking about this at Moparfest this past weekend and I thought the position of the fan in the shroud was the important measurement.

Jason

[burdar]

You want to shoot for the blades being half in and half out of the shroud.  However, if that puts you really close to hitting the radiator, you obviously need to move the fan back so you have clearance.

[CUDA JAS]

You want to shoot for the blades being half in and half out of the shroud.  However, if that puts you really close to hitting the radiator, you obviously need to move the fan back so you have clearance.

And if you can get the fan in closer to the rad, but you are further into the shroud is that ok / better?

Jason

[burdar]

I believe the distance from the blades to the radiator is more critical if you DON'T have a shroud.  I think I read that the optimal distance from the blades to the radiator WITHOUT a shroud is 2".

If you have a shroud, you need to shoot for half in and half out.  If you end up farther in and you can't move the blade back you either have to live with it or build another shroud that puts the fan blade in the ideal location.  I wouldn't worry about it though unless you are having cooling issues.  The blades being a little farther into the shroud won't be ideal but that doesn't mean you are going to automatically have problems.

[EMCD]

thanks. I'm going to use the factory mopar 26" shroud and mount it to my champion radiator with J type cage nuts. I have ARP studs on that mount the pulley to the pump and with the clutch fan I'm guessing it will eat about 1/2 out the full inch stud. is 1/2 with lock-tight enough to hold it on w/o the fan flying off at 4k RPM? if not, what length bolts should I get?

[YellowThumper]

Distance from the radiator to fan is important without a shroud.

With a shroud the rad distance is irrelevant. Mid portion of fan should be as close to shroud opening as possible. As typically this is also the smallest opening area. Too far in and fan will be trying to suck thru rad and push air out of shroud. Lots of turbulence there. Too far out it it will suck outside surrounding air. Think of it as a tube with a sealed fan on one end of it. Tube could be 2 inches or 6 feet long and the same air will be pulled thru it.

Mike

[EMCD]

so I mounted the clutch fan, drove it hard in traffic for about an hour in 75* temps. it never got higher than 180-185 tops. All this w/o a shroud. think I should just hold off on the shroud? the distance from the fan to the radiator roughly 1".

[YellowThumper]

The point I typically try to make on fan setups such as you have posted is is to define what your intended vehicle goal is.
Location climate also is a big factor.

If the bulk of your driving is as what you just described and the average ambient temperature is consistent, then leave as is.
If outside temperatures are frequently higher then add a shroud.
Another scenario is stop and go traffic and or even waiting in long lines at car shows. Lack of forward movement will also plus the need for a shroud.

Spirited driving will obviously raise the temps. And a shroud will help this as well.

I went with dual electrics on mine for this exact reason.
Often it is in the 90s where I live and many times the traffic is at a stand still. I can idle all day with them no problem.

Overall my vote would be to say yes because they are not expensive and they do work.
Mike.

[EMCD]

I'm in Denver, so I gets hot. I had dual electric fans and they sucked. They sucked big time. I spend a lot of good $$ on them and they impeded airflow. I'll mount the shroud next weekend. It cannot hurt, only will help in the long run.

[dfrazz]

I'm in Denver, so I gets hot. I had dual electric fans and they sucked. They sucked big time. I spend a lot of good $$ on them and they impeded airflow. I'll mount the shroud next weekend. It cannot hurt, only will help in the long run.

Please post a pic of how you mount the shroud on your aluminum rad.  I'll be doing this in a month or so.